Checker for furnaces



Nov. 28, 1950 F. AH. MACKENSEN CHECKERy FOR FURNACES Filed Dec. 16, 19442 Sheets-Sheet l Nov. 28, 1950 F. H. MAcKENsEN CHECKER FOR FURNACES 2Sheet-s-Sheet 2 Filed Dec. 16, 1944 Patented Nov. 28, 1950 lCI-IECKER,FOR FURNACES Fred. H. Mackensen, Bettendorf, Iowa, assignor to MexicoRefractories Company, Mexico, Mo., a corporation of Missouri ApplicationDecember 16, 1944, Serial No. 568,431

6 Claims. l

The present invention relates to high temperature furnace constructionand particularly to the regenerating chambers of heating furnaceswherein a checker arrangement of heat absorbing units is made for thepurpose of utilizing the heat of the Waste gases as they pass from theheating chamber to the stack or chimney. Such devices have been thesubject matter of considerable development as witnessed by the followingLetters Patent; Bigelow No, 1,916,458, McKelby No. 2,107,675, Milner No.2,257,392, wherein the structural features of the checker chamber arestressed. In other Letters Patent such as No. 2,108,871 and No.2,303,741 stress is placed upon the cleaning of checkers.

It is the purpose of my invention to provide a new type of checker unitwhereby the checker construction is practically self-cleaning so that itis not necessary to clean or disturb the checkers during a campaign inorder to maintain their efficiency at a high level.

It is a further purpose of my invention to pro vide individual checkerunits of such a nature that they can be arranged in piers in the checkerchamber in such relation to each other as to disperse the air and gas toall parts of the chamber thus obtaining uniform temperatures andproviding more heating area per cubic foot of chamber volume. Theparticular layout of the piers 0f checker units will, of course, varybecause of the great variety of diferent designs of furnaces and sizesof chambers. However, the fundamental design of the refractory unitswhich comprise the checker elements that make up the piers, makes itpossible to individually vary the construction without varying theindividual design of the checker unit and without losing any of theadvantages thereof.

The nature and advantages of my invention will appear more fully fromthe following description and the accompanying drawings wherein apreferred form of the invention is shown. It is to be understoodhowever, that the drawings and description are illustrative only and arenot to be taken as limiting the invention, except insofar as it islimited by the claims.

In the drawings:

Figure 1 is a vertical sectional View transversely through a portion ofa check chamber in a regenerator open hearth furnace;

Or' or) Figure 2 is a sectional view taken at right angles to Figure 1;

Figure 3 is a longitudinal sectional View through a preferred form ofchecker unit employed in accordance with my invention;

Figure 4 is a plan View of the unit;

Figure 5 is a longitudinal sectional view through a top unit employedin. building the piers of checker units;

Figure 6 is a plan view of a slightly different form of checker unitwherein the unitpis made up of segments;

Figure 7 is a view in side elevation of the checker unit shown in Figure6; and

Figure 8 is a plan view of one of the segments of the unit shown inFigure 6.

In checker chambers of regenerator furnaces, the waste gases arecirculated from the heating chamber in one direction to heat therefractory elements in the checker chamber for a certain length of time,and then the air flow is reversed so that heated refractories give uptheir heat to the air going into the heatingV chamber, This means thatwaste gases may carry with them particles in suspension, condensablevapors and even large particles so that the horizontally extendingsurfaces in the checker chamber, and any surfaces in the checker chamberthat form substantial pockets with a supporting surface more nearlyhorizontal or as nearly horizontal as the angle of repose of theparticles, will collect the particles.

According to my invention I propose to provide a checker brick which,because of its shape, I refer to as an hour glass unit. In the drawingsa unit of this character is shown in cross section at I0, Figure 3. Bothends Hand I2 of the unit are larger in internal and external diameterthan the mid portion I3 of the unit. The unit is made of a suitablerefractory material for use in open hearth furnace checker chambers.This unit has iiat top and bottom surfaces which are substantiallyparallel to each other so that several of the units I0 may be stackedone upon the other in the manner shown in Figure l of the draw-yfurnaces there is a direct passage upward through the roof l 5 andhorizontally to the heating chamber. There is usually a supporting meansin. the

tiplicity of channels in the checker chamber,h i5

some of the channels being inside the units and other channels beingbetween the units: The

piers may be spaced and staggered in anyfsuitf.- able form to providefor thebest distributienet;

the air channels in the checker chamber It is immaterial Whether the gaspassing through the chamber is going up or down,insofarasobtain-` ing athorough contact of the gas with there.- fractory checker units is.`-concerned. The particular hour. glassshape oftheindividual checker unitsprovides alternate surfaces vertically through. the checkerchamberagainstlwhich the gas. isA directed..` Inside-the piers. there arealtornate' restrictions and expansions in cross section of the passages.This islikewise true outside" thepiersbutythe restrictions are at Ythelevel where the greatest Vcross section insidethe piers.

exists. The angle made by the surfaces of; the checker-.units ill with ahorizontal line ismuch greater than the 4angle of repose for anyparticles that are carried over from the heating chamber. If. vapors.condense and form deposits, the air circulation around Ythe piers andthrough'the piers tends to remove any accumulation of material at aparticular point on a unit.- The sev-- eral checker units stacked oneupon theother mayggof, course, be cemented together as desired. Unitsare'molded quite smooth and are. matched carefully in mounting one ontop the other so as to leave no ledges projecting to invite `the accu-..

mulation of Aforeign particles. Referring. now to Figure 5 of thedrawings, this yngure illustrates a top checker unit lila. Thischeckerunit is essentially the same as that shown in Figures 3 and. 4 ofthedrawings` :except that Vit has itsupper* edge .I9 tapered .as shownso as to prevent. the.

accumulation of particles at .the top Vedgeof the unit;

Itmay be desirable from'a molding standpointV to'make the checker unitsin more than one piece. Figures 6, 7 and 8 illustrate a checkerunit/which is made up of four pieces. 20'is'shown in Figure 8 asv beingsemicircular in cross-section and tapering from 'one end to the other'soasto provide surfaces 2l. and22' ofthe rightr contour, VFour cithesepieces 28' are then cemented together or otherwise connected so thatth'eyprovidea complete unit 23 wherein the joints 24 between horizontaladjacent units are staggered circumferentiallycof rthe assembly. The'.Vertical faces of'the units 2t are of' such AshapeV that they can beprovided'with tongue and grooved .elements'to facilitate'uniting. theindi' vidual pieces 20 into a 'complete'checker'unity I iindthat achecker chamber constructed with I piers made with the checker unitdisclosed herein has thedistinct advantage that itis self-cleaning.

so' that it is not necessary to cleanI the checker unit during acampaign, Since there is no cleaning done, I haveno difficulty with'thechecker An individual piece' iii) units being pushed out of place orfalling. The whole construction of the checker unit provides for a highefficiency of the refractories since I obtain a maximum heating area percubic foot of chamber volume. For example, I can provide an effectiveheating surface of approximately three square feet of heat for eachcubic foot of chamber volume.

It is believed that the foregoing description will enable those skilledin this art to understand and practice the invention disclosed herein.Having thus described myjnvention, I claim:

1. A checker installation for regenerative furnaces comprising asupporting structure, and

#hollow annular piers of refractory material resting on said structureand spaced from each other and open at both ends, thereby providing airpassages. through thepiers and between them, the piers comprisingsections increasing in cross sec- :tional' area. alternated withsections decreasing in cross sectional area, the surfaces where thedirections change being curved in the direction corresponding to thelength of the piers.

2. A checker installation for regenerative furnaces comprising asupporting structure, and hollow annular piers of refractorymaterial'resting on said vstructure and spaced from each' other. andopen at. both ends, thereby providing air passagesthrough the piers and.between"them;. the piers comprising sections increasingincross'.sectional area alternated with'sections` decreasing in cross sectionalarea, Vthe slope' of Ythe surfaces in both sectionsbeingso small asVsubstantially: to `prevent accumulation of fine particles. carriedby-waste gases into said air. passages, the surfaces.. where thedirections change being curvedv in theA direction corresponding to thelength ofthe piers;

3. A checkerinstallation for regenerativefur: naces comprising a.supporting structure; and hollow annular piersof refractory material'rest'- ingon said structure and spaced from each other and open atbothends, thereby providing air pas-r sages through the piers and betweenthem; the; pierscomprising sections increasing in crosssec` V tionalarea alternated with sections decreasing in cross sectional area, the`slope .of .the sur# faces in both sections being so small assubstantially to prevent accumulation of iine particles carl-1 ried. bywaste gases into said' air passages, 'the top and bottom ends of saidpiers being at the points of. greatest cross sectional area,.the surf:faces Where the directions change-being curved; in the directioncorresponding to.. the length of'. the piers,

4. A checker unit of refractoryv material come; prising a hollowbody'vwith its opposite endsisub-' stantially equalin shape and size sothat units.' may be stacked, said body gradually.. decreasing in crosssection from .its ends toward the center;y said bodybeing composed of apair of.likesec-V tions tapering from .end to end,` the small'ends` ofthe two sections being joined..

5..A checker unit of .refractory material com; prising a hollowbodyiwith itsopposite ends'substantially Aequal in. shape and size sothat units'. maybe stacked, said body `gradually decreasing in crosssectionv from .itsends toward the centen.v said. body'being composed ofa .pair of like. seca tions tapering from end. to end,.th`e small lends;of the two sections beingjoinedgsaid sections each comprising twosemiannular like pieces, joined together, the longitudinal jointsAbetween pieces of' one section being. staggered .withi`re-i spect tolongitudinal joints in the adjacent.sec... tions.

2, 532, 1 1 2 5 6. A checker unit of refractory material for theREFERENCES CITED top of a pier of a regenerative furnace comprising Thefollowing references are of record in the a hollow circular body havingits major portions me of this patent: substantially symmetrical about isvertical and horizontal axes, said body gradually decreasing 5 UNITEDSTATES PATENTS in cross section from its ends to its center, the NumberName Date bottom face of said body being flat to permit 1,897,270Mitchell Feb. 14, 1933 stacking on the top of a column, the upper edge1,951,579 Pohl et al Mar. 20, 1934 of said body being tapered to an edgeto prevent 2,107,675 McKelvey Feb. 8, 1938 a-,imulatlon of particles atthe top edge of sald w FOREIGN PATENTS FRED H, MACKENSEN, Number CountryDate 242,083 Great Britain Nov. 2, 1925 445,045 Great Britain Apr. 3,1936

